Preparation of New Inorganic Consolidated Materials Using Mechanochemical Phenomena and the Consolidation Mechanism

利用机械力化学原理，由硅酸钾溶液(水玻璃)、氢氧化铝和高岭土反应合成了新型无机固结材料。为了制备固结材料，在干燥条件下机械球磨增强氢氧化铝和高岭石的机械力化学现象是非常重要的。机械球磨使它们的反应活性显著提高，其溶解度约为未球磨的1000倍。Al的低配位数的形成对反应活性的提高起到了重要作用。Als+离子在水玻璃中的溶解有助于固结机制的形成。溶解离子促进了水玻璃的聚合，形成了固结材料。为了开发更实用的材料和工艺，提出了球磨前的热处理。该处理加速了氢氧化铝的脱水，使氢氧化铝变得多孔化，在短时间内易发生球磨非晶化。因此，即使以较低的能量球磨也可以激活粉末。与常规砂浆相比，用活性粉末制备的固结材料具有更高的抗弯、抗压强度和更好的耐水性。以高岭土为原料，固结材料的性能也得到了很大的改善。本项目中的综合材料显示出实用材料的潜力。机械化学法不仅是粉末制备的重要工艺，也是材料设计的重要工艺。

New inorganic consolidated materials were synthesized by the reaction between potassium silicate solution (water glass), aluminum hydroxide and/or kaolinite, using mechanochemical phenomena. In order to prepare the consolidated materials, it was very important to enhance the mechanochemical phenomena of aluminum hydroxide and kaolinite by mechanical milling in a dry condition. Mechanical milling made their reactivity remarkably enhanced and they became approximately 1000 times as soluble as non-milled. Formation of low coordination number for Al played an important role in enhancement of the reactivity. Dissolution of Als+ ion of aluminum hydroxide into water glass contributed to formation of the consolidation mechanism. The dissolved ion promoted polymerization of water glass, resulting in synthesis of consolidated materials. To develop more practical materials and process, heat treatment before milling was proposed. The treatment accelerated dehydration of aluminum hydroxide and made the hydroxide porous, resulting in easy amorphization by milling in a short time. Accordingly, even milling with lower energy could activate the powder. The consolidated materials prepared with the activated powder exhibited higher bending and compressive strength and better water-resistance than conventional mortar. In case of using kaolinite as a starting material, moreover, the properties of the consolidated materials became much better. The consolidated material in the present project exhibited a potential of a practical material. Mechanochemical process was recognized as an important process not only for powder preparation but also for materials design.